Active remote sensing may be conceptualized as viewing radiation reflected and/or emitted from a certain location in one or more wavelength regions. Active remote sensing typically utilizes one or more sources of radiation (e.g., infrared, visible, or ultraviolet light) to illuminate a target area while measuring the reflected, scattered and/or emitted radiation at one or more receive detectors. Such remote sensing may be performed from a moving platform or from a stationary location, each of which may be spatially remote from the target area.
One method for performing active remote sensing is to stare at an area with a single detector, while illuminating the area with one or more wavelengths of radiation. Various sources of noise, however, may lower the signal-to-noise ratio (SNR) of the measurement. Examples of such noise typically present in active remote sensing include solar background radiation, 1/f noise (i.e., noise whose power varies inversely with frequency), atmospheric turbulence, and/or scintillation, and noise from varying reflectivity.
Thus, there is a need in the art to perform active remote sensing, using compact efficient transmitters and compact receivers while maintaining a high signal-to-noise ratio.